‘The End of an Era.’ Marissa Mayer Reflects on Her Time as Yahoo CEO

After nearly five years at the helm of Yahoo, Marissa Mayer is bidding an optimistic farewell to her company.

Mayer, who became CEO of Yahoo in 2012, posted on Tumblr a copy of an email she sent employees Tuesday as Verizon completed its $4.5 billion acquisition of the one-time internet giant’s operations. As previously planned, Mayer announced her resignation “given the inherent changes to my role.”

“While reaching this moment has certainly been a long road traveled, it marks the end of an era for Yahoo, as well as the beginning of a new chapter —it’s an emotional time for all of us,” she wrote in the email titled “Nostalgia, Gratitude, and Optimism.” “Looking back on my time at Yahoo, we have confronted seemingly insurmountable business challenges, along with many surprise twists and turns. I’ve seen our teams navigate these hurdles and mountains in ways that have not only made Yahoo a better company, but also made all of us far stronger.”

Mayer will leave Yahoo with what’s expected to be a $23 million severance package. That comes even though many investors struggle to look back on her tenure as positively as she did in her email. When Mayer first joined Yahoo from Google (GOOGL), hopes were high that the new CEO would be able to restore Yahoo back to its former glory. Mayer made a series of expensive bets, including the acquisition of Flurry and Tumblr in her time at the helm—but Yahoo’s core internet business still failed to impress.

Meanwhile, Yahoo’s share price jump of 228% during Mayer’s time there has largely been attributed to Yahoo’s holding in Chinese e-commerce giant, Alibaba. (The company is helmed by one of Fortune‘s World Greatest Leaders Jack Ma.)